Sound absorber for compressors

ABSTRACT

The invention relates to a sound absorber assembly for encased refrigeration compressors. Two cup-shaped members are slidably and telescopically joined to form a main chamber of selectively variable size. A partition in one of the cup elements divides the main chamber into two sub-chambers and the partition is movable to allow any desired volume ratio between the sub-chambers to be selected. A throttle passage having the opposite ends thereof in respective fluid communication with the sub-chambers is incorporated into or connected to the partition.

United States Patent 1 1 1111 3,750,840 Holme [45] Aug. 7, 1973 [54] SOUND ABSORBER FOR COMPRESSORS 1,682,316 8/1928 Williams 181/57 X 2,325,905 8/ 1943 Caulfield 181/56 [751 3:3; 32:??? 2%; 32: 2: 3,220,506 11/1965 Vemet 181/56 x I w. FOREIGN PATENTS OR APPLICATIONS 73 Dan! A l 1 Assume Nmdbora Denmark 800,799 12 1950 Germany 181/56 [22] Filed: Sept. 27, 1971 .2 App]. 1 4 3 :rimary [gamma-moths? Willldnson ssistant xaminer-Jo n onza es I Related US. Application Data Anomqhwaync Eamm [63] Continuation of Ser. No. 859,545, Sept. 19, 1969.

[30] Foreign Application Priority Data [57] ABSTRACT Oct 8' 1968 Germany P 18 0 7215 The invention relates to a sound absorber assembly for encased refrigeration compressors. Two cup-shaped s21 U.S. c1 181/57, 181/61, 181/63, members are slidably and telescopically joined to fvrm 417/312 a main chamber of selectively variable size. A partition -51 1m.c1. r0111 1/08, F04b 21/00 the P elements divid main amber 8 p f s 181/56, 6] 62, 63, into two sub-chambers and the partition is movable to 181/64 R 64 A; 417/312 allow any desired volume ratio between the sub- 1 a chambers to be selected. A throttle passage having the [56] References Cited opposite ends thereof in respective fluid communica- UNITED STATES PATENTS tion with the sub-chambers is incorporated into or con- 1 nected to the partition. 3,042,138 7/1962 -Reinert 181/64 R 3,125,182 181/61 UX 1 Claim, 2 Drawing Figures 3/ 1964 Early SOUND ABSORBER FOR COMPRESSORS This is a Continuation, of appln. Ser. No. 859,545, filed Sept. 19. 1969.

The invention relates to asound absorber for compressors, particularly encased refrigerant compressors, and comprising two chambers connected by a'throttle passage, two cup-shaped elements pushed one into the other at their open ends forming a chamber and this being divided by an intermediate dished element inserted into one of the cup-shaped elements.

Normally sound absorbers are separately designed and manufactured for each type of compressor, since the sizes of the sound absorber chambers and of the throttle passages vary with each compressor and in accordance with the use to which they are to be put. This however is uneconomical. The problem appears in particularly acute form in the field of encased refrigerant compressors, where each manufacturer must offer a fairly large number of compressors, graded according to capacity and incorporating sound absorbers, .the technical data of which vary. I

A sound absorber is known in which there is inserted into a first cup-shaped element the open end of a second such element, so that a prescribed noise-absorbing chamber is created. Furthermore, two intermediate dish-shaped elements, the axial position of which can be selected as required, are inserted in the first cup. In this way a first noise-absorbing chamber is created between the base of the second cup and the first dished element, a second sound-absorbing chamber between the two dished elements, and a third chamber between the second dished element and the first cup, this third chamber either not being utilizableat all or only in certain'circumstances. A disadvantage here is that four components are necessary to form two sound-reducing chambers, variable independently of each other, and that it is not possible to go below the smallest size of the first chamber which is determined by the height of the first dished element and of the second cup-shaped element.

The object of the invention is to provide a sound absorber of the initially described kind which, whilst being of simpler construction, offers the possibility of greater variation in the mutually independent dimensions of the two chambers.

According to the invention, this object is achieved by the cup-shaped elements which accommodates the intermediate dish-shaped element being inserted in the other cup-shaped element.

This results in a sound absorber, the two chambers of which are defined by only three components. The size of the two chambers can be adjusted independently of each other. By displacing the intermediate dished element in the associated cup-shaped element the size of one chamber can be altered, and by displacing the two cup-shaped elements relatively to each other the size of the other chamber can be altered. if the two cupshaped elements are pushed fully one into the other,

and the intermediate dished element occupies a middle position, extremely small noise-absorbing chambers for compressors of low capacity are produced from the same components which are also suitable for relatively large sound-reducing chambers for compressors of greater capacity.

In the known sound absorber a tube pushed through the intermediate dished member constitutes the throttle passage. In order to achieve a satisfactory throttle action, the tube must be of a certain length. This prevents reduction in the size of the chambers.

In a further aspect of the invention, very small soundabsorbing chambers can also be created if there is fitted on the base of the intermediate dished element a plate containing a channel-shaped depression which, together with the base, forms the throttle passage.

The invention will now be described in more detail by reference to an embodiment illustrated in the drawing, in which:

FIG. 1 shows a longitudinal section through the sound-absorber of the invention, and

FIG. 2 shows a cross-section on the line A A of FIG. I.

The sound-absorber consists of a first cup-shaped element 1, in which is inserted an intermediate dished element 2, a second cup-shaped element 3, which is pushed over the first cup-shaped element 1, a passage plate 4, an inlet tube 5 and an outlet tube 6. The passage plate 4 contains a channel-shaped depression 7 which, together with the base 8 of the intermediate dished element 2, forms a throttle passage 9. This leads from a hole 10 in the plate 4 to a hole 1 l in the intermediate dished element 2. All the parts are interconnected by soldering, which may possibly be carried out after preliminary spot welding.

The cross-section of the sound-absorber as seen in FIG. 2 is so selected that the sound-absorber can be accommodated between the wall of the case and the motor compressor in a hermetically encased small refrigerating machine. In the present instance the unit is used as a pressure sound-absorber. The three components 1, 2 and 3 between them define two soundabsorbing chambers 12 and 13. Within wide limits, the two chambers can be brought to any required size independently of each other. If the second cup-shaped element 3 is pushed downwards, the size of the chamber 12 is reduced, while the chamber 13 remains unchanged. If the second cup-shaped element 3 and the intermediate dished element 2 are pushed downwards at the same time, the size of the chamber 13 is reduced, whereas the chamber 12 remains unaltered.

I claim:

1. A sound absorber assembly for compressors comprising two cup members with one cup member telescopically disposed in the other to form a main enclosed chamber, a partition element mounted in one of said cupmembers to divide said main chamber into a total of two sub chambers having a selected volume ratio to provide optimum noise absorption characteristics, said partition element including a planar portion with a flange in surrounding reation thereto, an insert in abutting engagement with said planar portion and having a sinuous shaped recess which forms an enclosed throttle passage in cooperation with said planar portion,.an aperture in said planar portion providing fluid communication between one end of said throttle passage and one of said subchambers and an aperture in said insert providing fluid communication between the other end of said throttle passage and the other of said subchambers.

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1. A sound absorber assembly for compressors comprising two cup members with one cup member telescopically disposed in the other to form a main enclosed chamber, a partition element mounted in one of said cup members to divide said main chamber into a total of two sub chambers having a selected volume ratio to provide optimum noise absorption characteristics, said partition element including a planar portion with a flange in surrounding reation thereto, an insert in abutting engagement with said planar portion and having a sinuous shaped recess which forms an enclosed throttle passage in cooperation with said planar portion, an aperture in said planar portion providing fluid communication between one end of said throttle passage and one of said subchambers and an aperture in said insert providing fluid communication between the other end of said throttle passage and the other of said subchambers. 